The protoMIRAX hard X-ray imaging balloon experiment

Abstract

Context. The protoMIRAX hard X-ray imaging telescope is a balloon-borne experiment developed as a pathfinder for the MIRAX satellite mission. The experiment consists essentially in a coded-aperture hard X-ray (30-200 keV) imager with a square array (13 × 13) of 2 mm-thick planar CZT detectors with a total area of 169 cm 2 . The total, fully-coded field-of-view is 21 • × 21 • and the angular resolution is 1 • 43 . Aims. The main objective of protoMIRAX is to carry out imaging spectroscopy of selected bright sources to demonstrate the performance of a prototype of the MIRAX hard X-ray imager. In this paper we describe the protoMIRAX instrument and all the subsystems of its balloon gondola, and we show simulated results of the instrument performance. Methods. Detailed background and imaging simulations were performed for protoMIRAX balloon flights. The 3σ sensitivity for the 30-200 keV range is ∼1.9 × 10 −5 photons cm −2 s −1 for an integration time of 8 h at an atmospheric depth of 2.7 g cm −2 and an average zenith angle of 30 • . We developed an attitude-control system for the balloon gondola and new data handling and ground systems that also include prototypes for the MIRAX satellite.Results. We present the results of Monte Carlo simulations of the camera response at balloon altitudes, showing the expected background level and the detailed sensitivity of protoMIRAX. We also present the results of imaging simulations of the Crab region. Conclusions. The results show that protoMIRAX is capable of making spectral and imaging observations of bright hard X-ray source fields. Furthermore, the balloon observations will carry out very important tests and demonstrations of MIRAX hardware and software in a near space environment.

Hyper-Heuristics based on Reinforcement Learning, Balanced Heuristic Selection and Group Decision Acceptance

“…This problem refers to real-time TeleMetry (TM) data transmission from a hard X-ray imaging telescope which is to be launched by a balloon and will operate between 40 to 42 km of altitude [57,58]. The On-Board Data Handling Subsystem (OBDH) is responsible for acquiring, formatting, and transmitting to the Ground Station (GS) all TM data generated by several subsystems (X-ray Camera (XRC), Attitude Control Subsystem (ACS)) of the space segment.…”

LECX: a cubesat experiment to detect and localize cosmic explosions in hard X-rays

“…The peak on the right is produced by a fixed-height pulser for peak width comparison. Taken from Braga et al (2015).…”

“…In order to predict the performance of LECX for observations of GRBs and related phenomena, we have carried out a series of Monte Carlo simulations taking into account typical GRB spectra and the predicted LECX background. Since the LECX's graded shield, which is the same as the one used in our balloon project protoMI-RAX (Braga et al 2015), has been shown by Castro et al (2016) to be very effective in absorbing most gamma-rays in the typical GRB energy ranges, and also in cutting off the lead and tin fluorescence, we do not expect to have any significant contribution of scattering and transmission of the burst photons in the collimator. We also expect that contamination from GRB photons scattering off the spacecraft structure will be negligible since there is very little material in the cubesat platform and the detector plane is well shielded from below.…”

“…The technology being developed for LECX builds upon what has been developed for the protoMIRAX project (Braga et al 2015), a balloon experiment that represents a prototype of the MIRAX (Monitor e Imageador de Raios X, in Portuguese) space mission (Braga 2006;Braga et al 2004).…”

Background and Imaging Simulations for the Hard X-Ray Camera of the MIRAX Mission

“…The balloon version of the instrument is called protoMI-RAX (Braga et al 2015) and will be launched for the first time from Cachoeira Paulista, SP, Brazil, in late 2016 for a ∼ 24-hour flight. The balloon flight will test several MIRAX subsystems in a near-space environment and will carry out imaging demonstrations of the camera by observing bright X-ray sources.…”